Changing your default python version on OSX

$ man python
$ which python
/usr/bin/python
$ python -V
Python 2.7.1
#
# temporarily change version
#
$ export VERSIONER_PYTHON_VERSION=2.6
$ python -V
Python 2.6.6
$ unset VERSIONER_PYTHON_VERSION
$ python -V
Python 2.7.1
#
# persistently change version
#
$ defaults write com.apple.versioner.python Version 2.6
$ python -V
Python 2.6.6

http://stackoverflow.com/questions/6998545/how-can-i-make-python-2-6-my-default-in-mac-os-x-lion

Python module search path

Recently a coworker came to me asking why after installing a module via pip that he couldn't import it into python.

Turns out pip was installing to a directory that wasn't in the search path aka sys.path

You can check your sys.path by saying "import sys" followed by "sys.path"

Make sure the directory pip is installing your module into is in sys.path

Here pass the "-v" to pip to find out where it installed the module like so:

sudo pip install nltk -v

http://docs.python.org/2/tutorial/modules.html